Low-Cost Wheels for Gearmotors

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BeligerAnt
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Low-Cost Wheels for Gearmotors

Post by BeligerAnt »

Following on from Dave's discussion (http://robotwars101.org/forum/viewtopic.php?f=1&t=1963) low-cost wheels to fit the 3mm shaft of the 12mm gearmotors are clearly something of a problem.

So, does anyone have any bright ideas? The Pololu wheels cost around £5, can we come up with anything cheaper?

One idea I had was getting 3D printed wheels from Shapeways and fitting nitrile O-rings as tyres. O-rings are available really cheaply, but how much would wheels from Shapeways cost? And does anyone have a design they are willing to make available?

O-rings are available from simplybearings.co.uk in all sizes, for example 4mm x 38mm OD £4 for 10 or £8 for 50! (Plus VAT, but P&P is only £1.50)

Your chance to show how brilliant you are by coming up with a good solution to this problem :)
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Re: Low-Cost Wheels for Gearmotors

Post by josh »

Not the cheapest option but there are a few people that use these wheels I designed. hubs from Shapeways with the following tyres

They are on my drive all day and several other people's robots although I can't remember who...
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BeligerAnt
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Re: Low-Cost Wheels for Gearmotors

Post by BeligerAnt »

Not really a cheap solution at about £9 a pair including tyres :(
So I guess Shapeways is not going to be a viable solution for a low-cost wheel...

Any other offers, anyone?
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Re: Low-Cost Wheels for Gearmotors

Post by haz »

hdpe rod + cricket bat grip?

its like £3 for a 500mm length of the hdpe iirc
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Re: Low-Cost Wheels for Gearmotors

Post by razerdave »

The problem with making wheels is the hole. Jonno's current kit wheels screw into the servo horn rather than the circular output. On the gearmotors, th D shaft, which I would imagine is not the easiest thing to cut out, will not fit most commercial wheels nor many you could make from plate or rod. The wheels I bought for St Jimmy had a 3mm round hole in them, like pete's green wheels on his DAD robot, and althought they were a tight fit to start with, that soon got ground out, and I have been tryng to fix them in place with all manners of epoxy glue and loctite since.
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Re: Low-Cost Wheels for Gearmotors

Post by josh »

No, those are not intended as a cheap fix. however they are a worthy replacement for the Robotmarketplace.com bling wheel.

I also have these push fit hubs that could be an easy fix in some cases. there is a set up cost for shapeways so the more you get in one model the cheaper they are per hub.
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Re: Low-Cost Wheels for Gearmotors

Post by peterwaller »

As I mentioned in the other thread these are cheap (32p inc vat) and are designed to be an interference fit on 3mm shafts.
http://www.mindsetsonline.co.uk/product ... id=1009819
The site is back up now and on my drive all day I have the cricket bat handle rubber stuck on.
I got it from ebay it had a diamond pattern and just streched to fit round the wheel.
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Re: Low-Cost Wheels for Gearmotors

Post by razerdave »

Are those green wheels just a straight 3mm hole though ? I have had wheels like that before and they just strip out.
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Re: Low-Cost Wheels for Gearmotors

Post by BeligerAnt »

If the wheels are designed to be an interference fit they should be OK as long as they are fitted once then left in place. If they are repeatedly removed and re-fitted the holes will wear.
Since there is a small boss on the wheel, it may be possible to cross-drill and add a grub screw to hold the wheel on the shaft.
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Re: Low-Cost Wheels for Gearmotors

Post by razerdave »

I'll get myself a pair and see how they hold out.
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